CVE-2026-110306: fast-uri vulnerable to URI scheme spoofing via percent-encoded scheme decoding
Noroxi assessment
Priority: Monitor (action score 24/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.25% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
- Fixed version: fast-uri fast-uri 2.4.8, 3.1.9, 4.2.3.
Low priority for now. Upgrade to fast-uri fast-uri 2.4.8, 3.1.9, 4.2.3 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
fast-uri is a dependency-free RFC 3986 URI parser and serializer for Node.js. In versions before 2.4.8, from 3.0.0 through 3.1.8, and from 4.0.0 through 4.2.2, fast-uri percent-decodes the scheme component with the legacy global unescape() function before validating it, so an input whose decoded scheme is a dangerous token is emitted as a live scheme even though RFC 3986 does not allow percent-encoding in a scheme and no other parser accepts it. An application that screens dangerous schemes on the raw input and then stores or renders the normalized or resolved result can turn an inert string into an executable javascript, data, or vbscript URL, producing a stored or reflected cross-site scripting vector, and the equal() comparison treats an encoded and a plain scheme as the same, which can bypass equality-based allowlists. The issue is fixed in fast-uri 2.4.8, 3.1.9, and 4.2.3, and users should upgrade to one of these versions or later. As a workaround, reject input whose scheme part contains a percent sign, or check the parsed scheme against an allowlist after normalization and use that same parsed result rather than the raw string.
- Published
- Oct 20, 2026
- Updated
- Oct 20, 2026
- EPSS
- 0.2% · 16th percentile
- CWE
- CWE-172
Report tools
Action score
24
Monitor
Low priority for now.
- CVSS
- 24 / 40 · 6.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · openjs
- 6.1
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (openjs). Independent of NVD's CPE analysis and usually ahead of it.
fast-uri fast-uri
- 2.4.8, 3.1.9, 4.2.3not affected
- before 2.4.8affected · semver
- 3.0.0 and later · before 3.1.9affected · semver
- 4.0.0 and later · before 4.2.3affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | node-ajv | from 0 | — |
| Debian:14 | node-ajv | before 8.20.0~ds+~cs7.2.4-1 | 8.20.0~ds+~cs7.2.4-1 |
| npm | fast-uri | from 3.0.0 · before 3.1.9 | 3.1.9 |
| npm | fast-uri | from 4.0.0 · before 4.2.3 | 4.2.3 |
| npm | fast-uri | before 2.4.8 | 2.4.8 |
| openSUSE:Tumbleweed | git-bug | before 0.11.0-3.1 | 0.11.0-3.1 |
Same product
fast-uri: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-110180fast-uri vulnerable to host confusion via unchecked WHATWG host canonicalization19Monitor
- CVE-2026-86818fast-uri vulnerable to mailto header injection via percent-encoded field-name desynchronization19Monitor
- CVE-2026-86472fast-uri vulnerable to inconsistent host case normalization via percent-encoded octets19Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-110095Oct 20, 2026 · fast-uri vulnerable to improper path equivalence in relative reference normalization14Monitor
- Later →CVE-2026-110725Oct 20, 2026 · fast-uri vulnerable to scheme injection via an unescaped first-segment colon in suffix references14Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| fast-uri fast-uri | 2.4.8 | Vendor (CNA) |
| fast-uri fast-uri | 3.1.9 | Vendor (CNA) |
| fast-uri fast-uri | 4.2.3 | Vendor (CNA) |
| debian:node-ajv | 8.20.0~ds+~cs7.2.4-1 · Debian:14 | Package registry (OSV) |
| npm:fast-uri | 2.4.8 | Package registry (OSV) |
| npm:fast-uri | 3.1.9 | Package registry (OSV) |
| npm:fast-uri | 4.2.3 | Package registry (OSV) |
| opensuse:git-bug | 0.11.0-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recordedsame day
- TodayNov 5, 2026+17 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- UlisesGasconremediation reviewer
- mcollinaremediation reviewer
- zekthreporter
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-8681835 days apartfast-uri vulnerable to mailto header injection via percent-encoded field-name desynchronization19Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- low · data or configuration can be modified
- Availability
- none
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality impact
- Low
- Integrity impact
- Low
- Availability impact
- None
Weakness class (CWE)
CWE-172 · Encoding ErrorCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Double EncodingCAPEC-120likelihood: Low · Medium
- Leverage Alternate EncodingCAPEC-267likelihood: High · High
- Using Leading 'Ghost' Character Sequences to Bypass Input FiltersCAPEC-3likelihood: Medium · Medium
- Embedding NULL BytesCAPEC-52likelihood: High · High
- Postfix, Null Terminate, and BackslashCAPEC-53likelihood: High · High
- Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-64likelihood: High · High
- Using Unicode Encoding to Bypass Validation LogicCAPEC-71likelihood: Medium · High
- URL EncodingCAPEC-72likelihood: High · High
ATT&CK techniques
Change log
- SSVC exploitation— → none
- Exploit maturity— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.